Why the Corporate Pension Gap Is Soaring

Companies Struggle as Low Rates, Other Forces Inflate Funding Needs

By

Vipal Monga

Updated Feb. 26, 2013 12:12 p.m. ET

When United Parcel Service Inc. said last month that it was taking a noncash charge of $3 billion tied to its pension plan, the package-delivery giant blamed what might seem like an unrelated event: the downgrade last summer of several big banks by Moody's Investors Service.

But the connection between the two incidents illustrates the complexities of calculating pension liabilities—and how little power companies have in keeping them...